The present invention refers to a method for determination of the amount of particles in gaseous media and a sampling device for performing the method.
In air conservation there is a large need for a simple method of measuring the amount of particles transported in gaseous media, e.g. in connection to discharge of pollution (emission) or a particle transport (mass per unit of time and surface) to a receiver (immission).
The measuring of particle emission in stacks and flues has hitherto mainly been carried out with use of manual methods. At such a measurement is on one hand the gas flow determined and on the other hand the mass concentration upon an isokinetic sampling on filters. The measurements require some calculations during and after the very sampling operation, whereby an especially trained staff is needed for these measurements. The performing of such a measurement requires a large number of filters, a comprehensive equipment for flow control for guaranteing isokinetic sampling and a particular system for gas flow determination. Each measurement requires the work of several men and it is thus very expensive as well regarding working as equipment costs.
A system for emission measurement in skylight turrets has earlier been developed in the USA and this system is based on so called "High Volume Samplers", but the sampling is in that case not made isokinetically whereby the accuracy of measurement is lower. The costs for the measuring equipment and the measuring work is also in this case very high.
Alternative methods for the measuring of immissions are based on a measurement of a mean concentration per unit of time and a mean wind velocity. If there is a correlation between the wind velocity and the concentration will here a systematic error in measurement be obtained. (A comparatively large number of samples are taken at low wind velocities when the immission is small and vice versa). A systematic error of measurement is also got as the sampling is generally brought about non-isokinetically.